Integrated control of citrus green and blue molds using Bacillus subtilis in combination with sodium bicarbonate or hot water

Abstract

Abstract Bacillus subtilis isolates F1, L2, and L2-5, isolated from citrus fruit surfaces were evaluated for control of citrus green and blue molds caused by Penicillium digitatum and P. italicum , respectively. These isolates were evaluated alone, or in combination with sodium bicarbonate (SB) or hot (45 °C) water treatment on artificially inoculated ‘Valencia’ and ‘Shamouti’ orange cultivars. Treated fruit were stored at 10±1 °C, and 90–95% relative humidity (RH) for 4 weeks. When applied alone, all isolates performed significantly better than the water control in checking the incidence of both green and blue molds, but were not as effective as the fungicide (quazatine plus imazalil) treatment. Isolate F1 was more effective than L2 and L2-5 in this respect. A significant increase in biocontrol activity of all isolates was observed when isolates were combined with SB, or when applied following hot water treatment. The treatments comprising F1 combined with SB or F1 applied following hot water treatment was as effective as the fungicide treatment, which gave 100% control of both green and blue molds on both cultivars.